you will need to generate an array of x and y values to plot in order to create a circle. You need to plot it just like you would any other equation. If you want to plot multiple equations on the same graph:
I'm new to Matlab and I'm not too knowledgeable about how to do things in it but i have a quick question which would help me a lot:
I have a plot of points, and I need to add a circle, with radius R and centre on the origin - how do I do this?